West Nile Virus has been detected in Pittsfield, and health officials are responding.
Last week, the Massachusetts Department of Public Health confirmed the existence of West Nile virus in the city’s mosquito population. This is the third positive test in the city and the seventh in Berkshire County this summer. Working with the City of Pittsfield, the Berkshire County Mosquito Control Project has scheduled a truck-mounted spraying over a roughly one-mile area on the east side of the city starting at 10 p.m. The project’s superintendent Chris Horton says an earlier spraying in Richmond proved effective.
“We did a treatment in Richmond on Friday night," Horton said. "We had traps out there last night and trap catches were almost nil in the areas that we treated.”
According to the Massachusetts department of public health, West Nile virus first appeared in the United States in 1999. Since the initial outbreak in New York City, the virus has spread across the U.S. from east to west. Nationally, 2,734 human cases of the virus were reported to the Centers for Disease Control and Prevention in 2012. Gina Armstrong is the Director of Public Health for the City of Pittsfield. She says approximately 80 percent of people infected with the virus show no symptoms, while the remaining 20 percent experience flu-like symptoms, including fever, headache, and fatigue. She says the elderly and people with weakened immune systems are the most susceptible to the virus, but there are steps people can take to reduce their risk, like wearing long sleeves during peak hours from dusk to dawn.
“If people monitor their property once a week and they clean out the bird baths, empty out toys on the yard that can collect water," Armstrong said. "If it’s standing for a week it can breed a significant number of mosquitoes.”
Horton says the spraying will take three to four hours using an air compressor mounted on a truck releasing four to five gallons of the insecticide Duet at a rate of 0.62 ounces an acre. The targeted area will be from the intersection of Meleca Avenue and Williams Street to neighborhoods in Dalton Division. To avoid any related health issues, people should close windows and doors, turn off air conditioners, and stay inside during the spraying.
“The product is approved for residential use," Horton said. "It’s very low toxic. In terms of risk, the risk is considered negligible because the product never would have been approved by the EPA if there was any kind of a significant risk. Even if people were to come into contact with the product the way it’s applied, there’s still not a significant risk.”
The first human case of West Nile in Massachusetts this summer was reported after the story's broadcast. Armstrong and Horton both say now is the peak time for the virus’ transmission from birds to mosquitoes and the problem will remain until the area experiences a heavy frost. Horton says there was an uptick in preemptive sprayings this year because of high mosquito numbers resulting from flooding in June.
“By thinning out the infected mosquitoes, we are also slowing down the progression of the virus," he said. "The virus is going back and forth between the mosquito and bird population. When we thin out the infected mosquitoes, it makes it less likely that more birds will become infected. They call that the amplification of the virus and we’re trying to stop the amplification.”
Less than one percent of people infected with West Nile will develop severe illness, such as encephalitis or meningitis. These symptoms can include coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis. According to the Massachusetts Department of Public Health, there were at least five fatal human cases identified between 2002 and 2012 in the state. All fatalities were among people 80 years of age or older.